2.Proceedings of the Royal Society of Londonby Royal Society (Great Britain) by Royal Society (Great Britain) (1896)"WHF Hermann von Helmholtz was born in Potsdam, on August 31, 1821. His father
was a Professor of Literature in the Gymnasium of that town. ..."

3.The Library of Original Sources by Oliver Joseph Thatcher (1907)"PHYSICS AND CHEMISTRY Hermann von Helmholtz HERMANN HELMHOLTZ was born at Potsdam,
Prussia, Aug. 31, 1821. He received his degree in medicine from Berlin in ..."